- *CrAl- or AlCr-based combined with a ternary nitride coating*

The coating properties of (AlCrX)N can be combined with AlTiN [155,156]. There are some coating systems that contain V in a nitride coating to tailor tribological properties (formation of lubricant oxides), such as (TiV)N [157], (CrV)N and (CrMo)N [103]. The combination with (TiSi)N is focused on high hardness and oxidation stability [158].


The comination with quarternary nitride layers is a very complex approach. Many coating properties are influenced in parallel. The following systems have been explored: (AlTiSi)N [151,159], (AlCrSi)N [139,160], (TiTaAl)N [161].


The arc deposition of an fcc-(Al,Cr)ON layer on top of an fcc-(Al,Cr)N-based coating resulted in improved wear resistance [162]. The combination of alternating single layers consisting of a nitride fcc-(Al*x*Cr1−*x*)N layer followed by an oxide coating (Al*x*Cr1−*<sup>x</sup>*)2O3 with a hardness of up to 22 GPa was demonstrated [163].
